1 files changed, 22 insertions, 3 deletions

diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 03f3b05e8ec1..3e108f154cb6 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -16,6 +16,7 @@
 
 #include <linux/atomic.h>
 
+struct optimistic_spin_queue;
 struct rw_semaphore;
 
 #ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
@@ -23,9 +24,17 @@ struct rw_semaphore;
 #else
 /* All arch specific implementations share the same struct */
 struct rw_semaphore {
-        long                    count;
-        raw_spinlock_t          wait_lock;
-        struct list_head        wait_list;
+        long count;
+        raw_spinlock_t wait_lock;
+        struct list_head wait_list;
+#ifdef CONFIG_SMP
+        /*
+         * Write owner. Used as a speculative check to see
+         * if the owner is running on the cpu.
+         */
+        struct task_struct *owner;
+        struct optimistic_spin_queue *osq; /* spinner MCS lock */
+#endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
         struct lockdep_map      dep_map;
 #endif
@@ -55,11 +64,21 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
 # define __RWSEM_DEP_MAP_INIT(lockname)
 #endif
 
+#ifdef CONFIG_SMP
+#define __RWSEM_INITIALIZER(name)                       \
+        { RWSEM_UNLOCKED_VALUE,                         \
+          __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock),     \
+          LIST_HEAD_INIT((name).wait_list),             \
+          NULL, /* owner */                             \
+          NULL /* mcs lock */                           \
+          __RWSEM_DEP_MAP_INIT(name) }
+#else
 #define __RWSEM_INITIALIZER(name)                       \
         { RWSEM_UNLOCKED_VALUE,                         \
           __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock),     \
           LIST_HEAD_INIT((name).wait_list)              \
           __RWSEM_DEP_MAP_INIT(name) }
+#endif
 
 #define DECLARE_RWSEM(name) \
         struct rw_semaphore name = __RWSEM_INITIALIZER(name)